北京通过车牌限制来限定汽车数量，并在空气特别糟糕的时候制定计划限制最古老和污染最严重的车辆上路。

Beijing has used license plate restrictions to limit the number of cars and set out plans to keep the oldest and most polluting vehicles off roads when air is especially bad.

youdao

北京通过车牌限制来限定汽车数量，并在空气特别糟糕的时候制定计划限制最古老和污染最严重的车辆上路。

Beijing has used license plate restrictions to limit the number of cars and set out plans to keep the oldest and most polluting vehicles off roads when air is especially bad.

youdao